Hi All

I have been doing a lot of research on the internet trying to find the best configuration for my Deye 8KW Inverter. I found the powerforum very helpful in my research and am hoping that some of you can answer the following question

I have read alot about creating the perfect bell curve and re-arranging ones load throughout the day to run things like geyers and pool pumps when there is solar production and then using batteries at night to run the the essential less power hungry devices. I have tried my best to achive this but have noticed that currently my solar production seems to mimic my load consumption. So when load demand is high, solar production is high but when load demand is low solar production is low. This is not ideal. I want my Deye converter to be producing maximum power throughout the day regardless of what my load requirements are.

I have setup my Deye Inverter so that priority is Load First ( not battery ) and have also set "Zero Export to Load"

Ideally what I am trying to achieve is that from about 7:30-800 in the morning when solar starts to generate the lnverter will manage the load and charge the battery with any excess power. What I am expecting to see is that once the battery reaches 100% that the load is then powered by solar and any shortfall is taken from the battery. But what I am seeing is that once the battery reaches 100% is seems that the load is then powered by Eskom ( the inverter is not wanting to let the battery drop below 100% as this point)

My System of Times is set that by 5pm my batteries are 100% and therafter they deplete to about 30% the next morning at 7am in a stepp down approach of each slot dropping about 20%. Then from 7AM to 5PM they climb to 100% with another few step up time slots. Even though I have set my system to have batteries at 100% by 5PM I find most days this is achied by 12 Noon

Apart from when there is load shedding I have "Grid Charge" disabled

So I guess my question is

• Why is my load pulling from the Grid instead of the battery even when the battery is 100%?

• My theory was that seeing as I set my SOC to 100% by 5PM ( starting at 12 noon) that once the battery reaches 100% any time during this period the system wants to keep the battery at 100% until 5PM thus any power the load needs in addition to what the solar is providing will come from the Grid.

• If this is the case then how do you set the inverter to charge to 100% by 5PM but to also use the battery instead of Eskom when the load exceeds solar prodution? So in essence battery is used when solar production is not enough for current load but thereafter solar will top up the battery assuming load requirments come down enough to allow this.

• I am suspsecting that the inverter wants to keep the battery at 100% once it reaches this value as it has no way of knowing that if it allows it to deplete below 100% if it will be able to get it back up to 100% by 5PM.

• My inital thought is to break up the 12 - 5 slot into shorter slots of 2 - 3 hours. So maybe a 12-2 with a soc of 80% and 2-5 slot with a soc of 100%

• It seems as if my batteries are getting to 100% to quickly ( even though my setting is load first ) so perhaps I must make the required SOC settings a lot lower per time slot thus allowing the load to be powered by the batteries more in the theory that the inverter will still be able to reach its 100% by 5PM but this time closer to 5PM than 12 Noon

All advice appreciated

Thanks

Edited April 14, 20251 yr by MarkZA79

10 minutes ago, MarkZA79 said:

how do you set the inverter to charge to 100% by 5PM but to also used the battery instead of Eskom when the load exceeds solar prodution?

The inverter is just doing exactly what you are telling it to do: Keep the battery level to a minimum level of 100%.

If you want to allow the battery to run down, maybe you could set the desired minimum battery level to something around 80% or 90%.

That way, if there is enough sunlight, the battery will keep charging up to 100%, but if you are running a slightly higher load in short burts, you will draw the battery down from 100% to 80% or 90% and then charge back up again once the demand has dropped.

In principle, the inverter will set the generation to match your demand. One analogy of electricity is like your blood sugar level. Not exactly the same science, but you can't have too much of it in the system, you've got to either use it up, or convert and store the excess.

The way to keep your inverter busy all day at maximum capacity is to ensure you are running enough large loads all the time (wasteful if not needed), or are storing the surplus power to a bigger battery bank, or else you must then export power to the grid. But that brings me to asking what are your other work mode settings? Because you are sending power to the grid, but are you somehow limiting your grid export?

I think I finally understandy my issue

In my mind SOC per timeslot was the maximum the inverter would charge per timeslot ( even though I have been talking about 100% by noon all along the penny did not drop)

However that is wrong. SOC is the minimum the battery will discharge to in that timeslot. So argument sake if SOC is set 40% by noon and battery was at 30% from previous evening but solar production is enough it will charge to 100% ( even though SOC is 40% ). But the SOC of 40% will also allow the battery to discharge to meet the load spikes and then charge up again to 100% if solar is sufficient. The only other consideration is to have Grid Charge ticked to supplement charging the batteries to 100% by 5PM in case solar is not enough after perhaps a load spike at around 3PM

It's like your water meter, if nothing is using water, it won't be turning, but, the potential to supply you water is still there.

Same with PV, it will only send power as is needed.

You will need to use your battery, even if from 12 til 6, so that there is somewhere for the PV power to go.

When battery is full, it will only send the power that is needed (load).

A perfect curve is only achievable with either a big enough battery, or by feeding back to the grid.